21671199 has 32 divisors (see below), whose sum is σ = 35354880. Its totient is φ = 13010400.

The previous prime is 21671197. The next prime is 21671213. The reversal of 21671199 is 99117612.

It is not a de Polignac number, because 21671199 - 2¹ = 21671197 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21671197) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 38629 + ... + 39185.

It is an arithmetic number, because the mean of its divisors is an integer number (1104840).

Almost surely, 2^21671199 is an apocalyptic number.

21671199 is a deficient number, since it is larger than the sum of its proper divisors (13683681).

21671199 is a wasteful number, since it uses less digits than its factorization.

21671199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708 (or 702 counting only the distinct ones).

The product of its digits is 6804, while the sum is 36.

The square root of 21671199 is about 4655.2335064957. The cubic root of 21671199 is about 278.8009911610.

The spelling of 21671199 in words is "twenty-one million, six hundred seventy-one thousand, one hundred ninety-nine".